With the advent of the ubiquitous age, demands for high-quality voice and audio services based thereon have increased more and more. In order to satisfy the increasing demands, there is a need for an efficient voice and/or audio codec.
With the advancement of networks, the bandwidth provided for the voice and audio services has been extended and a scalable voice and audio encoding/decoding method of providing a high-quality audio at a high bit rate and providing a voice or a middle-quality or low-quality audio at a low bit rate has been considered.
In the scalable encoding/decoding, the quality of the services can be improved and the encoding/decoding efficiency can be enhanced, by variably providing the bandwidth as well as the bit rate. For example, by reproducing a wideband (WB) signal from a super-wideband (SWB) signal when an input signal is the SWB signal or reproducing an SWB signal from a WB signal when an input signal is the WB signal.
Therefore, methods of generating an SWB signal from a WB signal have been studied.